1. Field
Method and system for measuring amniotic fluid volume.
2. Background
Amniotic fluid is the fluid within the pregnant uterus enclosed by the fetal membranes and placenta. Amniotic fluid helps protect and cushion the fetus and plays a role in the development of various fetal organs including the lungs, kidneys, and gastrointestinal tract. Too much or too little amniotic fluid may be associated with abnormalities in development of the fetus or other pregnant complications.
Currently, ultrasound techniques are used to provide a measurement of amniotic fluid volume referred to as the amniotic fluid index (AFI). AFI may be assigned by adding linear determinations of amniotic fluid pocket depths and/or two-dimensional assessments of amniotic fluid pocket dimensions. AFI data obtained may be compared to data listing normal values for the pregnancy stage of the patient for which an AFI is determined. AFI may provide a way to screen for certain abnormalities during pregnancy. However, AFI is not a good predictor of actual amount of amniotic fluid.
Accurate assessment of amniotic fluid volume may be important for various reasons. First, it provides an indication of fetal stress. Fetal stress may cause the amniotic fluid volume to decrease due to fetal renal metabolic changes and decreased urine output, which constitutes the main generator of amniotic fluid. Second, low amniotic fluid volume renders the fetus at risk for compression of the umbilical cord, which is often an emergency situation. Accordingly, an accurate assessment of amniotic fluid volume may be useful in screening for certain fetal stress conditions and/or other pregnant complications.